summaryrefslogtreecommitdiffstats
path: root/src/BlockState.cpp
diff options
context:
space:
mode:
authorMattes D <github@xoft.cz>2019-08-23 16:17:05 +0200
committerMattes D <github@xoft.cz>2019-08-24 12:03:38 +0200
commit02fbf1686565ace00df5af938d95fbe18783fc37 (patch)
treee109749b5823f758d605dd2a8f5d2c8b8b22878b /src/BlockState.cpp
parentUpgrade Appveyor's MSVC (diff)
downloadcuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar.gz
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar.bz2
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar.lz
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar.xz
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.tar.zst
cuberite-02fbf1686565ace00df5af938d95fbe18783fc37.zip
Diffstat (limited to 'src/BlockState.cpp')
-rw-r--r--src/BlockState.cpp167
1 files changed, 167 insertions, 0 deletions
diff --git a/src/BlockState.cpp b/src/BlockState.cpp
new file mode 100644
index 000000000..4e2607bd3
--- /dev/null
+++ b/src/BlockState.cpp
@@ -0,0 +1,167 @@
+#include "Globals.h"
+#include "BlockState.h"
+
+
+
+
+
+BlockState::BlockState():
+ mChecksum(initializeChecksum())
+{
+ // Nothing needed yet
+}
+
+
+
+
+
+BlockState::BlockState(const AString & aKey, const AString & aValue):
+ mState({{aKey, aValue}}),
+ mChecksum(initializeChecksum())
+{
+}
+
+
+
+
+
+BlockState::BlockState(std::initializer_list<std::pair<const AString, AString>> aKeysAndValues):
+ mState(aKeysAndValues),
+ mChecksum(initializeChecksum())
+{
+}
+
+
+
+
+
+BlockState::BlockState(const std::map<AString, AString> & aKeysAndValues):
+ mState(aKeysAndValues),
+ mChecksum(initializeChecksum())
+{
+}
+
+
+
+
+
+BlockState::BlockState(std::map<AString, AString> && aKeysAndValues):
+ mState(std::move(aKeysAndValues)),
+ mChecksum(initializeChecksum())
+{
+}
+
+
+
+
+
+BlockState::BlockState(const BlockState & aCopyFrom, std::initializer_list<std::pair<const AString, AString>> aAdditionalKeysAndValues):
+ mState(aCopyFrom.mState)
+{
+ for (const auto & kav: aAdditionalKeysAndValues)
+ {
+ mState[kav.first] = kav.second;
+ }
+ mChecksum = initializeChecksum();
+}
+
+
+
+
+
+BlockState::BlockState(const BlockState & aCopyFrom, const std::map<AString, AString> & aAdditionalKeysAndValues):
+ mState(aCopyFrom.mState)
+{
+ for (const auto & kav: aAdditionalKeysAndValues)
+ {
+ mState[kav.first] = kav.second;
+ }
+ mChecksum = initializeChecksum();
+}
+
+
+
+
+
+bool BlockState::operator ==(const BlockState & aOther) const
+{
+ // Fast-fail if the checksums differ or differrent counts:
+ if ((mChecksum != aOther.mChecksum) || (mState.size() != aOther.mState.size()))
+ {
+ return false;
+ }
+
+ // Slow-check everything if the checksums match:
+ return std::equal(mState.begin(), mState.end(), aOther.mState.begin());
+}
+
+
+
+
+
+const AString & BlockState::value(const AString & aKey) const
+{
+ auto itr = mState.find(aKey);
+ if (itr == mState.end())
+ {
+ static AString empty;
+ return empty;
+ }
+ return itr->second;
+}
+
+
+
+
+
+UInt32 BlockState::initializeChecksum()
+{
+ removeEmptyKeys();
+
+ // Calculate the checksum as a XOR of all mState keys' and values' checksums
+ // This way we don't depend on the std::map's ordering
+ UInt32 res = 0;
+ for (const auto & kv: mState)
+ {
+ auto partial = partialChecksum(kv.first) ^ partialChecksum(kv.second);
+ res = res ^ partial;
+ }
+ return res;
+}
+
+
+
+
+
+void BlockState::removeEmptyKeys()
+{
+ for (auto itr = mState.begin(); itr != mState.end();)
+ {
+ if (itr->second.empty())
+ {
+ itr = mState.erase(itr);
+ }
+ else
+ {
+ ++itr;
+ }
+ }
+}
+
+
+
+
+
+UInt32 BlockState::partialChecksum(const AString & aString)
+{
+ UInt32 shift = 0;
+ UInt32 res = 0;
+ for (auto ch: aString)
+ {
+ UInt32 v = static_cast<UInt8>(ch);
+ v = v << shift;
+ shift = (shift + 1) % 24;
+ res = res ^ v;
+ }
+ return res;
+}